Sealants useful in aerospace and other applications must satisfy demanding mechanical, chemical, and environmental requirements. The sealants can be applied to a variety of surfaces including metal surfaces, primer coatings, intermediate coatings, finished coatings, and aged coatings. Adhesion promoters are typically added to sealant formulations to enhance adhesion of the various components to each other and to the surfaces to which the sealant is applied. Ways to provide improve surface adhesion while maintaining other advantageous properties of a sealant are continuously desired.
Sulfur-containing polymers such as polythioethers and polysulfides are useful in aerospace applications. Examples of suitable polythioethers and polysulfides are disclosed, for example, in U.S. Publication Nos. 2005/0010003, 2006/0270796, 2007/0287810, 2009/0326167, and 2010/036063, each of which is incorporated by reference in its entirety.
Copolymerizable sulfur-containing adhesion promoters containing terminal adhesion promoting groups and used in sulfur-containing polymer compositions are disclosed in U.S. application Ser. No. 13/529,183. Sulfur-containing polymers having bis(sulfonyl)alkanol metal ligands incorporated into the backbone of a sulfur-containing polymer and/or as terminal groups of a sulfur-containing polymer are disclosed in U.S. application Ser. No. 13/923,903 and U.S. application Ser. No. 13/923,941.